Method and apparatus for treating saws with heat



A. J. HARRY. METHOD AND APPARATUS FOR TREATING SAWS WITH HEAT. APPLIC. \TIG.T HLED FEB-17,1921.

1,429,138, Patented Sept. 12,1922.

2 SHEETS-SHEET I.

INVENTUR A ro/Mrs v A. 1. HARRY.

METHOD AND APPARATUS FOR TREATING SAWS WITH HEAT.

I APPLICATION FILED FEB. I7, 1921. l,l29,1 88; ratentedSept. 1.2, 1922. v

2 SHEETS-SHEET l l r 2 0M ZL? ATTORNEYS f of East Cleveland, in the county of 'Guya-' Patented Sept. 12, ,1922.

uNrrE o s'r TES ALBERT JOSEPH HARRY, or EAST CLEVELAND, omo.

METHOD AND APPARATUS FOR TREATING SAWS WITH HEAT.

T 0 all whom it may concern:

Be it known that I, ALBERT J HARRY, a citizen of the United States, and a resident hoga and State of Ohio, have inventeda new and Improved Method and Apparatus for Treating Saws with Heat, of which the following is a full, clear, and exact description. p .This invention relates to apparatus for treating saws with heat, and has for an object the provision of a simple and economically manufactured, compact and eflicient apparatus for treating saws, particularly disk saws, to a definite temperature immediately after they have been taken from the furnace.

Another object is. to provide an efficient and simple apparatus in which the saws while being so treated to a definite temperature can be kept straight and flat and are",

therefore, not liable to warp or bend as is sometimes the case.

A further object resides in the provision of a process or series of steps whereby, the high-speed steel of which the saws are made is produced in a better condition by the particular process adopted'than heretofore has been the case. I 4 A still further object resides in the articular'construction and arrangement'of parts and inthe particular sequence of steps in the process applied, hereinafter claimed, and

' shown in the accompanying drawings. '35

In general, it is known to be old to quench high-speed steel, of which saws are made, in a bath at 1150 F., thus tempering itat the same time'to the maximum toughness. Hitherto it has been customary to put heavy articles, where possible, into a lead bath at 1150 F. directly from the furnace at 2250 F. p

In accordance with my method, however, I adopt a somewhat similar process with the additional feature that during the time that the saws, or other high-speed steel articles, are being subjected to the lower-temperature after coming from the furnace, they are subjected to a certain pressure between flat'surfaces to keep them straight. These flat sur- Application filed February 17, 1921; Serial No. 445,859.

faces are also heating elements which subject the article to the'desired temperature for-the proper length of time.

The heating surfaces flat articles of steel are subjected to pressure electrical heating elements in a manner to be hereinafter described.

The invention is illustrated in the draw-- in s, of which-"- igure 1 represents a front view of the up paratus by which the process embodying my The preferred embodiment of my inven tion, as shown in' the drawing, comprises :a press having'a base plate 1 which can be attached in any suitable manner to a -floorfrom which extends a vertical supporting.

between which the form arts of a press and. are constructed as column or rib 2 to the upper end 'of which a top plate 3 is connected. Between the plates 1 and 3 a pair of spaced, vertically extendmg, parallel guide bars 4 are disposed. These guide bars are adapted to receive apertured lugs, such as 5, disposed on opposite sides of aslidable heating unit 6. This heating un'itis kept in its vertical movement by the bars 4 and has on its upper surface a journal block 7 to which is pivoted a connecting rod 8. This rod 8 is pivotally connected to a crank arm 9 which is pivoted'at 10 in the I or top plate 3 and forms part of' a handle member 11.

upper block The operation of the handle member in one direction or the other moves theupper sliding heating plate 6 toward and away froma similar heating unit such as 12 which may be securely fastened in any suitable manner to-the base block or plate 1. i

In the process which is applied by means of the use of apparatus of this general type, high-speed steel articles, preferably flat articles such as'disk saws, are initially treated in a furnace to a temperature of approximatel 2250 F., after which they are quenc ed by being subjected to a lower temperature of.substantially 1150 F. Ordinarily this second step in the treatment is effected by plunging the saws into an oil bath at room temperature, after which the saws are drawn again in a lead bath at 1150 F. However, in this particular form of the second step, no means are provided for keeping the saws under pressure whereby they may be kept straight and prevented from warping. However, in accordance with my invention, I place the saws, or other articles, as soon as they are taken from the furnace, betweenthe heating plates such as 6 and 12 and subject them to a definite pressure for a proper length of time, and during this time supply heat to the plates 6 and 12 by electrical means so .that the saws or other articles are slowly cooled from 2250 F. down to 1150 R, which is approximately the temperature of the heating plates 6 and 12. T find that by thus treating the saws they are maintained straight and do not warp and that their mechanical and structural condition is such that they require no further heat treatment and are free from strains. Saws treated in this particular manner are found to be extremely tough and hard and are capable of doing much more work in use. The saving of time and labor by adopting this particular process is also considerable.

Tn Figures 3 and 4, I show one of the heat- 2 ing units or plates, such as 6 or 12, and a description of this will suffice for both since they are substantially identical. The plate shown in Figures 3 and f is in the form of a shell having a flat surface 13, preferably made. of nichrome or Monelmetal, which 7 does not deteriorate under high temperatures, which is bent over along its circumference and provided with a flange such at 14.

This flange portion is provided at intervals with ear portions, such as 15, suitably pierced with apertures and connected up to a base or cover plate 16 made of any suitable material, such. as steel, provided with simlla'rears 17. The cover 16 and plate 13 are held together by; bolts 18 co-ope'rating with the ears 15 and 17. As abovedescribed, the shell is in the form of a shal-- low circular cup. Within this shell, and made integral with the plate 13, are a plurallty of radially extending reenforcing ribs such as 19 which help to strengthen the plate. These ribs are formed integrally with the shell, which may be cast. These reenforcing ribs 19 extend from the inner face of the heating surface 13 to the-bottom plate 16. The resistor element, which is in the form of a suitably coiled and spaced wire-20, 1s disposed beneath but spaced from the heating plate 13- and is in the form of a wire made preferably of some material such as nlchrome. This wire is disposed in suitably provided grooves such as 21 in theupper surface of a layer of refractory matei have received.

mamas rial, such as fire clay, and which is represented by the numeral 22. Beneath this layer of .fire clay is a layer of soft asbestos or magnesia 23, and beneath this layer is a piece of hard asbestos lumber such as 24:. This piece 24 lies against the bottom plate of the cover 16. A suitable connection, such as 25, extends from the resistor element 20 to an outside power source which ofiers the required amount of electric current to heat 7c the plate 13 to the desired temperature, I which in this case is approximately 1125 F. The surface heat to 1125 F. insteadof 1150 is to allow for a higher heating of the saw.

In order to accurately determine the temperature of the heating plate, I may provide any suitable form of pyrometer, which can be inserted or attached to each heating plate in any desiredmanner, to indicate the temperature thereof. This particular construction is not shown for the reason that it may be' provided in any particular manner and form no essential part of my invention. The process in which this apparatus is used is simply to take the saw or other article from the furnace at 2250 F. and place it in this press and hold it therein under a suitable pressure the proper length of time until the temperature of the heating plates is reached by the saw or article. After this temperature is reached, the saw can beremoved from the press and can be then cooled in air or may be disposed of in any other way following this operation. No further treatment isrequired of the articles, and they are capable of operating under the conditions above mentioned and possess theabove-mentioned highly advantageous qualities due to the treatment they ice It is, of course, ,apparent that minor modifications in the materials and arrangement ofthe structure above mentioned can be adopted without departing from the spirit of the inventionas set forth.

' What I claim is 1. A method of treating flat metallic articles ,such as saws,-which comprises subjecting them .to a high heat, then substantially immediately subjecting them to a 11115 lower heat, and subjecting them to pressure duriri g their-subjection to the lower heat.

2. method of treating flatmetallic articlessuch. as steel saws, which comprises subjecting them to a high heat, then sub- 1201' stantially immediately subjecting them to a lower heat, subjecting them-to pressure during theirsubjection to the lower heat, and then permitting them to cool in the atmosphere free from pressure and heat.

3. A method of treating flat metallic articles such as high-speed-steel saws, which comprises subjecting them to a temperature of substantially 2250 F., then substantially immediately subjectingthem to a temperarec ture of 1150 F.', and subjecting them to a stantially immediately subjecting them to a small pressure during their subjection to temperature of 1150., Sub ecting them to a this lower temperature. small pressure during their subjection to 10 4. A method of treating flat metallic this lower temperature, and then allowing- 5 articles such as high-speed steel saws, which them to cool in an atmosphere free of both comprises subjecting them to a temperapressure and heat. ture of substantially 2250 F., then sub- ALBERT JOSEPH HARRY. 

